The present invention relates to an average movement articulator capable of being set for free movement, wherein an upper frame is moved longitudinally, vertically, laterally, or rotatably relative to a lower frame or the upper frame is pivotted vertically in analyzing occlusion, restoring decayed teeth and making crown bridges.
When restoring decayed tooth or making a crown bridge or a denture, working casts of the patient's upper and lower jaws are formed, the working casts are mounted on an articulator, such as a simplified, small-sized articulator, an average movement articulator or an adjustable articulator, the working casts are occluded or eccentrically moved, the movement of the patient's jaws is measured, the articulator is adjusted on the basis of the results of trial occlusion and measurement and the working casts are mounted on the adjusted articulator for the analysis of occlusion, the restoration of a decayed tooth, making a crown bridge or a denture, and the adjustment of a crown bridge or a denture.
Such an articulator is constructed by pivotally mounting an upper frame for supporting an upper working cast on a lower frame for supporting a lower working cast. The upper frame is opened or closed hingedly on the pivoted shaft for center occlusion and backward condyle path movement to make the upper and lower working casts simulate the movement of the patient's jaws.
The conventional articulators, however, have the following disadvantages.
The simplified, small-size articulator is able to hold small working casts of only two to four teeth and incapable of accurately simulating motions of jaws, because the simplified, small-size articulator has an inclination of condyle path allowing only slight motions of jaws and is capable of vertical opening and closing motion.
The average movement articulator is capable of hinged opening and closing motion and the condyle path movement is fixed to an average movement. Therefore, the average movement articulator is able to move only within a limited angular range and unable to deal with various cases.
The adjustable articulator is provided with a plurality of adjusting mechanisms to enable the adjustable articulator to simulate the movement of human jaws and has the same size as the human maxillary structure. Therefore, the adjustable articulator has a complicated construction, is very large and heavy and is very cumbersome to use.
A free movement articulator has an upper frame, a lower frame and springs interconnecting the upper and lower frames. However, the free movement articulator is unable to simulate the movement of the jaws and unable to function accurately for the restoration and adjustment of a decayed tooth since the frame is twisted or a play exists on the pivoting shaft.
Accordingly, it is an object of the present invention to provide an average movement articulator capable of being set for free movement and of solving the foregoing problems in the prior art.